As indicated in the referenced application titled "Single-Drum Conveyor Belt," conventional article conveyor systems of the type commonly used at cashier or check-out stations in supermarkets and the like have generally been characterized by the use of two cylindrical drums for each belt, one of the drums being a driven drum and the other an idling drum serving primarily to define the path of travel of the belt, to provide the required belt tautness, and to adjustably provide the necessary frictional contact of the belt against the driven drum.
With the above referenced single-drum concept, the disadvantages of the conventional two-drum systems have effectively been overcome, such disadvantages having been perceived in the area of high manufacturing costs stemming from the second drum requirement and the rigid frame structure and intricate adjustment means required for establishing the required belt tautness, and in the area of high maintenance costs stemming from the time and labor that is required for changing belts and for adjusting and maintaining proper tension and balance.
Although the single-drum conveyor belt system overcomes these long-prevailing cost disadvantages, the requirement of an external motor and a connecting drive chain or belt, which has also characterized conventional conveyor systems, has still remained, such requirement presenting additional disadvantages particularly when available space for a conveyor installation is limited or when the system is to be installed in an area where dust or other foreign particles are likely to collect on the motor and the connecting belt or chain. The use of an external motor for driving the driven drum has further tended to be objectionable, especially in those instances where the motor might be subject to slight displacement during the course of usage, and the belt subject to stretching or the chain to deterioration.